1. Field of the Invention
This invention relates generally to a cell necrosis apparatus, and more particularly to a cell necrosis apparatus with an introducer and deployable electrodes.
2. Description of the Related Art
Current open procedures for treatment of tumors are extremely disruptive and cause a great deal of damage to healthy tissue. During the surgical procedure, the physician must exercise care in not cutting the tumor in a manner that creates seeding of the tumor, resulting in metastasis. In recent years, development of products has been directed with an emphasis on minimizing the traumatic nature of traditional surgical procedures.
There has been a relatively significant amount of activity in the area of hyperthermia as a tool for treatment of tumors. It is known that elevating the temperature of tumors is helpful in the treatment and management of cancerous tissues. The mechanisms of selective cancer cell eradication by hyperthermia are not completely understood. However, four cellular effects of hyperthermia on cancerous tissue have been proposed, (i) changes in cell or nuclear membrane permeability or fluidity, (ii) cytoplasmic lysomal disintegration, causing release of digestive enzymes, (iii) protein thermal damage affecting cell respiration and the synthesis of DNA or RNA and (iv) potential excitation of immunologic systems. Treatment methods for applying heat to tumors include the use of direct contact radio-frequency (RF) applicators, microwave radiation, inductively coupled RF fields, ultrasound, and a variety of simple thermal conduction techniques.
Among the problems associated with all of these procedures is the requirement that highly localized heat be produced at depths of several centimeters beneath the surface of the skin.
Attempts to use interstitial local hyperthermia have not proven to be very successful. Results have often produced nonuniform temperatures throughout the tumor. It is believed that tumor mass reduction by hyperthermia is related to thermal dose. Thermal dose is the minimum effective temperature applied throughout the tumor mass for a defined period of time. Because blood flow is the major mechanism of heat loss for tumors being heated, and blood flow varies throughout the tumor, more even heating of tumor tissue is needed to ensure effective treatment.
The same is true for ablation of the tumor itself through the use of RF energy. Different methods have been utilized for the RF ablation of masses such as tumors. Instead of heating the tumor it is ablated through the application of energy. This process has been difficult to achieve due to a variety of factors including, (i) positioning of the RF ablation electrodes to effectively ablate all of the mass, (ii) introduction of the RF ablation electrodes to the tumor site and (iii) controlled delivery and monitoring of RF energy to achieve successful ablation without damage to non-tumor tissue.
Thus, non-invasive procedures for providing heat to internal tissue have had difficulties in achieving substantial specific and selective treatment.
Examples illustrating the use of electromagnetic energy to ablate tissue are disclosed in: U.S. Pat. No. 4,562,200; U.S. Pat. No. 4,411,266; U.S. Pat. No. 4,838,265; U.S. Pat. No. 5,403,311; U.S. Pat. No. 4,011,872; U.S. Pat. No. 5,385,544; and U.S. Pat. No. 5,385,544.
There is a need for a cell necrosis apparatus with at least two electrodes that are deployable with curvature from an introducer. There is another need for a cell necrosis apparatus with at least two electrodes that are selectably deployable with curvature from an introducer to a desired deployed geometric configuration. There is yet a further need for a cell necrosis apparatus that provides deployable electrodes that create a variety of different geometric cell necrosis lesions.
Accordingly, an object of the invention is to provide a cell necrosis apparatus that provides tissue reduction at selected anatomical sites.
Another object of the invention is to provide a treatment apparatus to create cell necrosis.
Still another object of the invention is to provide a cell necrosis apparatus that has at least two electrodes which are deployable from an introducer with curvature and a third electrode which is deployable with minimal curvature.
Yet another object of the invention is to provide a cell necrosis apparatus with selectively deployed electrodes.
A further object of the invention is to provide a cell necrosis apparatus that is configured to deploy electrodes selectively at a tissue site to create a desired cell necrosis lesion.
These and other objects of the invention are achieved in a cell necrosis apparatus including an introducer with a distal end sufficiently sharp to penetrate tissue, an energy delivery including a plurality of electrodes and a slidable sensing member. Each electrode of the plurality of electrodes has a tissue piercing distal end and is positionable in the introducer as the introducer is advanced through tissue. At least one electrode of the plurality of electrodes is deployable with curvature from the introducer. The slidable sensing member is positionable within the introducer and electrically coupled to the energy delivery device. The sensing member is configured to measure a property of the energy delivery device or at least one electrode of the plurality of electrodes.
In another embodiment, a cell necrosis apparatus has an energy delivery device that includes a first RF electrode with a tissue piercing distal portion and a second RF electrode with a tissue piercing distal portion. The first and second RF electrodes are positionable in the introducer as the introducer is advanced through tissue and deployable with curvature from the introducer at a selected tissue site. A groundpad electrode is coupled to the first and second RF electrodes. A first sensor is coupled to the groundpad electrode.